When changing dropdown value there is error in console and model is not updated

[ianc]

Hi,
I have got problem with setting current value of selected dropdown value. 
Now when I am changing dropdown the error occurs "Uncaught TypeError: undefined is not a function"
and model is not updated. 
What is wrong with code ?
My problem is described by code available at  http://jsbin.com/ritor/

[ianc]

Propely formated link: 
http://jsbin.com/ritor/9/edit 

[ianc]

Ok, problem solved here http://jsbin.com/deyuse/8/edit
I attached function to model :)